HOTAIR and breast cancer: Though Gupta et al. [17] identified increased HOTAIR expression in a cross-sectional study of primary and metastatic breast carcinoma, and Kleer et al. [8] identified high levels of EZH2 in breast cancer metastases, this is the first study to look at matched primary and metastatic breast cancers and correlate EZH2 protein and HOTAIR expressions in archival material.